Hey! I'm Rae, the Pagan editor here, and I can field a few of these.

A "pantheon" historically was a temple dedicated to all gods and not just one. The word now is used to refer to the groupings of gods that are associated with various beliefs system. For example, Zeus, Apollo, Aphrodite and all the Greek gods are the Greek pantheon. Shiva, Durga, Kali and Parvati are all part of the Hindu pantheon. I hope that helps explain it.

Fiona wrote a great article about what a Book of Shadows is and you can read it here